Stirring or scraping apparatus for use in tanks for clarifying liquids and for other purposes



Feb. 5, 193

R o. STOKES 1,990,011

snmmie on scRAPmcT'APPARA'rus FOR USE IN TANKS FOR CLARIFYING LIQUIDS AND FOR OTHER PURPOSES Filed Sept. 18, less 7 sneets sneet 1 1;99o,o11 N TANKS FOR ES 7 Sheets-Sheet 2 1935- R. o. STOKES STIRRING OR SCRAPING APPARATUS FOR USE I CLARIFYING LIQUIDS AND FOR OTHER PURPOS Flled Sept 18 1955 Feb. 5,

Feb. 5, 1935. STOKES 1,990,011

STIRRING 0R SCRAPING APPARATUS FOR USE IN TANKS FOR CLARIFYING LIQUIDS AND OTHER PURPOSES Filed Sept. 1933 7 Sheets-Sheet 3 "1 F l E 2 j l i 5 4 p ,a 1k u 1 I a -L i--- 1. I

Feb. 5, 1935.

STIRRING 0R SGRAPING CLARIFYING LIQUIDS Filed S O. STOKES APPARATUS FOR US AND FOR OTHER ept. 1a, 1953 ANKS FOR SES 7 Sheets-Sheet 4 E I PU Feb. 5, 1935. v R, Q STOKES 1,990,011

STIRRING 0R SCRAPING APPARATUS FOR USE IN TANKS FOR CLARIFYING LIQUIDS AND FOR OTHER PURPOSES Filed Sept. 18, 1935 I 7 Sheets-rShee-t 5 Feb. 5, 1935. R Q STOKES 1,990,011

STIRRING OR SCRAPING APPARATUS FOR USE IN TANKS FOR CLARIFYING LIQUIDS AND FOR OTHER PURPOSES Filed Sept. 18, 1933 7 Sheets-Shet 6 Feb. 5, 1935. Q 510 55- STIRRING 0R SCRAPING APPARATUS FOR USE IN TANKS FOR CLARIFYING LIQUIDS AND FOR OTHER PURPOSES Flled Sept 18, 1953 7 Sheets-Sheet 7 Patented Feb. 1935 I stir 'STIRRING OR SCRAPING APEARATUS FOR 'LUSE IN TANKS FORLCLARKFYING. LIQUIDS AND EUR OTHER PURPOSES "Rupert Octavius StokesLondon; England Application September 18,1933; Serial No. 639,975

tiln Great Britain September 7, 1932 3 Claims.

-':.'lhew:invention: relates touth-ickeners andother .:zapparatus oi1a;. similars.nature inwhich aastirring or"scraping-arrangement is caused to re i *volve ina ltankicontaining. the suspension orlmix ture toqbetreated. :J. Such. apparatus.may find ap- ::..plication; to therconcentration of ores, for exam- ':-.=ple,i-byabstractingasome of the *water of suspenision'and to1thel clarifying of. liquids by removing material in suspension.

. .-:'According 130111118: present invention the stir- ".ring: or-rscraping arrangement is supported by .r-l'means of'trucks or. carriages-running on a track 1". rOundthe. edge of; the .tankand the drive is ob' .tainedby coupling one or more motors to one 3:; or more of the truck wheels, the electric supply to the rmotors being takenxthrough slip -rings mountedcentrally in relation to the tank.

jThe'accompanying drawings show how the in" vention: may be put into practice.

. .Therein, Figure -1 is a sectional elevation of a "-kclarifier; Figure 2 is a part plan of the same; Fig .ures'z3' and 4 .are sectional elevations to a larger scale of the discharge and.- inlet side respectively;

.uFigure 5 is a sectional plan of the driving car--- ':--of the periphery with a feed launder'2 from which theliquid to be :clarified is discharged'into the tankbymeans ofaplurality of openings 3. Discharge takes place over weir boards 4 located on"- an opposite arc of: the tank periphery into an ov--- erflow launder 5 from which the clarified liquid is discharged by the pipe 6 to be collected in any suitable manner.

The scraping arrangement comprises a framework 7 having three arms at an angle of about 120 to each other. The lower parts of the arms are near the conical base of the tank and are provided with oblique scraping blades 8 which tend to move the deposited solids towards a conical depression 9 at the centre of the base, from which they are discharged through an underflow pipe 10 by means of suitable pumpingmechanism (not shown).

The ends of the arms are provided with carriages 11, 12, 13 running on a rail 14 which is supported on the top of the circular tank wall 15. Two of these carriages 12 and 13 are trailers serving merely as supports for the weight of the has two flanged wheels.

to a well at the centre.

scraping arrangement. Each has a double flanged supporting wheel 16 and the carriage 12 is provided in addition with a guide wheel 17 engaging the inside. edge of the rail 14. The carriage 11 may also have a guide wheel 17 if de-: 5

sired The carriage 11 is a driving carriage provided with two double flanged wheels 18 each with a gear wheel 19 on its shaft meshing with a common pinion 2e. pinion 20 is driven by double reduction worm and spur gearing 21, 22 from an electric motor 23 mounted on the carriage.

"The electric supply to the motor is carried by means of leads 40 in conduit to along the arm at; the end of which the carriage 11 is mounted.

These leads are connected at the other end toil;

sliprings 24? mounted at the top of a column or -1nast'24 at the centre of the scraping arrzmgement The brushes 51 running on the slip rings 2% are connected by span wires 51 or by cable suspended on a messenger wire (not shown) to...z0 the starting gear suitably located outside the #tank periphery.

Another form of clarifier is shown in Figure 7. In this drawing the tank 1, scraper frame 7, discharge cone 9, underflow pipe if), carriages 111,25

"andi12, rail' i l and tank wall 15 may be seen.

These parts are similar to those already described except that the'carriage 12 as well as the carriage 13, which does not appear in the view shown,

' In this form of clarifier the weir board 4 forming the edge of the discharge launder 5 extends all the way round the tank and the feed is taken The feed supply to the well necessitates a launder 26 passing from 5 the outside of the tank tothe centre which is supported on a suitable girder structure 27. This provides accordingly a convenient support for the leads 51 which are taken as before to brushes 51 and thence to slip rings 24 mounted 40 on the column or mast 24 at the centre and above the supporting point of the feed launder. The centre end of the feed launder truss is supported on a ball thrust washer 23 mounted on the centre column 24.

It may be found adviisable in certain cases to apply the drive to more than one of the carriages. Moreover, the number of carriages to be used is not necessarily limited to three; the number will depend upon the conditions to be fulfilled by the apparatus. The invention is not limited to circular tanks, but can also be used with square tanks as described in British specification No. 248,679.

In such a case if the drive is only applied to one carriage it is probable that the small periodic variation in speed will not be found of any disadvantage. On the other hand, if all these carriages are to be driven, certain difficulties may be incurred, since the three carriages are at different phases of their periodic movement at any given time. With a direct current supply this difficulty be readily overcome by connecting the armatures of all three motors in series and the fields in parallel and operating the combination of three motors as a single shunt or compound wound motor. Other methods may also be devised for operating the three motors to compensate for the non-uniformity of speed in this case.

To guard against a stoppage which might have serious consequences it is advisable to fit an underspeed alarm to some suitable part of the apparatus. This would draw attention to a possible failure WlllCh might be caused by a slipping of the driving wheels on wet or greasy rails or by excessive loads on the arms or any other untoward occurrence. The alarm would then give the attendant the opportunity of rectifying the difiiculty before the consequences become serious.

A suitable form of alarm is shown in Figure 8 and comprises a star wheel 29 fitted to one of the trailing wheels 16 and co-operating with an arm 30 so as to raise the arm periodically and then allow it to fall without obstruction.

The arm 30 is connected to a dashpot 31 near by means of a bye-pass 33 with non-return valve 34'and to fall slowly, the speed of fall being adjustable by a screw 35 controlling the small ori- 17186 36 through the piston. Near the bottom of its travel the arm engages a push-button switch 37 or other suitable contact device closing the circuit to a bell or signal lamp or any other form of alarm.

At the correct speed of stirring arrangement 7 each point of the star wheel 29 will pick up the arm 30 during its fall from the previous point before it has had time to operate the alarm switch 37. If on the other hand the speed is too low or the stirring arrangement has stopped altogether, the arm 30 will actuate the alarm switch 37.

To guard against failure of the alarm if a stoppage should take place while the arm 30 is supported by a point of the wheel 29, the star wheel and arm are duplicated at 38, 39 and the second star wheel 38 has its point staggered in relation to the wheel 29, so that in every position one or other of the arms 30 and 39 is free to descend and actuate the alarm.

An alternative construction of alarm device is shown in Figure 9. In a casing 41 is mounted a gear pump 42 driven by suitable means from the wheel 16. The casing is filled with oil to the level 43 and the oil chamber is in communication with the gear pump by two L-shaped passages 44, 45, constituting the inlet and outlet respectively of the pump 42. In the outlet passage 45 there is a plunger 46 which permits a small amount of leakage. This leakage combined with that through the pump is suificient to allow the plunger to sink if the pumps stops due to the stoppage of the wheel 16. The plunger 46 has an insulating tip 47 serving to raise a spring 48 when the plunger is raised. The spring 48 has on it a contact block 49 which makes contact with a spring 50 when a failure allows the plunger 46 to fall.

What I claim is:

1. Apparatus for abstracting solid material from the liquid in which it is suspended, comprising in combination a tank to contain the suspension to be treated, a track round the edge of the tank, carriages running on said track, a device supported solely on said carriages to dip into the suspension, an electric motor driving at least one wheel of a carriage, a central mast on the moving device, slip rings on the said mast, leads from the slip rings to the motor and leads from the slip ring brushes to a point outside the tank.

2. Apparatus for abstracting solid material from the liquid in which it is suspended, comprising in combination a tank to contain the suspension to be treated, a track round the edge of the tank, carriages running on said track, a device supported solely on said carriages to dip into the suspension, an electric motor driving at least one wheel of a carriage, a central mast on the moving device, a feed launder supported at its discharge end on said mast, slip rings on the mast above the supporting point of the feed launder, leads from the slip rings to the motor and leads from the slip ring brushes to a point outside the tank.

3. Apparatus for abstracting solid material from the liquid in which it is suspended, comprising in combination a tank to contain the suspension to be treated, a track around the edge of the tank, three carriages running on said track, a three-armed device solely supported by its arms on the three carriages to dip into the Suspension, an electric motor on one carriage driving at least one wheel thereof, a central mast on the three-armed device, slip rings on said mast, leads from the slip rings to the motor, and leads from the slip ring brushes to a point outside the tank;

RUPERT OCTAVIUS STOKES. 

